Endoscopic septoplasty versus conventional septoplasty for nasal septum deviation: a systematic review and meta-analysis of randomized clinical trials

Background: Although conventional septoplasty is widely used to treat nasal septum deviation, it increases morbidity due to poor visualization, poor illumination, the need for nasal packing, and difficulty in evaluating of the exact pathology. These drawbacks are also encountered in endoscopic septoplasty. Our study aimed to compare the treatment and complication outcomes of conventional and endoscopic septoplasty. Methods: The authors searched five electronic databases for relevant clinical trials. The records were screened for eligibility. Data were extracted from the included studies. Outcomes were pooled as risk ratios (RR) or mean differences with 95% CIs using RevMan ver.5.4. Results: Our study included 13 randomized clinical trials with 735 patients. Our analysis revealed that endoscopic septoplasty was significantly (P<0.05) superior to conventional septoplasty for postoperative nasal obstruction relief, intraoperative and postoperative hemorrhage, and mucosal adhesion and synechiae across both long-term and short-term follow-ups. The following pooled RR values were found in short-term follow-up periods: [RR=1.20, 95% CI:=(1.09,1.32)]; [RR=0.27, 95% CI=(0.14,0.54)]; and [RR=0.16, 95% CI=(0.08,0.32)], respectively. Regarding persistent septal deviation and septal tear, endoscopic septoplasty had the upper hand only in short-term follow-up periods [RR=0.30, 95% CI=(0.17,0.53)] and [RR=0.26, 95% CI=(0.15,0.46)], respectively. Conclusion: Our analysis revealed that endoscopic septoplasty was significantly superior to conventional septoplasty in postoperative nasal obstruction relief rate and reducing the risk of intraoperative and postoperative hemorrhage, mucosal adhesion and synechiae, persistent septal deviation, septal tear, and surgery duration.


Introduction
The prevalence of a straight nasal septum is low, as it is highly susceptible to trauma in intrauterine life [1] . Globally, only 15% of women and 7% of men have a straight nasal septum [2] . A deviated septum can be asymptomatic or induce functional and esthetic abnormalities. A deviated nasal septum can also contribute to infection due to poor ventilation of the paranasal sinuses. Consequently, a deviated septum should be corrected if it causes functional or cosmetic problems [3] .
Killian et al. and Freer et al. independently developed and refined the concept of submucosal excision early in the previous century. Conventional septoplasty, first described by Cottle et al. in 1947, is a traditional surgery in which only the deviated part of the septum is removed, leaving as much cartilage and bone as possible [4] . However, this procedure has increased morbidity owing to poor visualization, poor illumination, relative inaccessibility, the need for nasal packing, and difficulty in evaluating the exact pathology [2] .
The endoscopic repair of septal deformities was first introduced by Lanza and Zinriech in 1991 [5] . Compared to traditional septoplasty, endoscopic septoplasty has many advantages, including improved visualization, accurate flap dissection with the removal of isolated deformities, a reduced risk of flap tears, and a smoother transition when combined with endoscopic sinus surgery [6,7] . However, despite these advantages, endoscopic septoplasty can be challenging because of frequent staining of the endoscope lens by blood from the incision site and difficulty in navigating the nasal passages [8] .
Evidence is required to assess the superiority of endoscopic septoplasty over conventional procedures. A previous metaanalysis by Hong et al. [9] included many low-quality nonindexed and observational studies in their pooled analysis, leading to potentially inconclusive results. In addition, there are newly published studies that compare both procedures. Therefore, in our study, we aimed to evaluate the treatment and complication outcomes of endoscopic septoplasty compared to those of conventional septoplasty.

Methods
The study was designed according to the Cochrane Handbook for Systematic Review of Interventions and reported following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA), Supplemental Digital Content 1, http://links.lww. com/MS9/A160 and (AMSTAR), Supplemental Digital Content 2, http://links.lww.com/MS9/A161 guidelines [10][11][12] . According to AMSTAR 2, our systematic review and meta-analysis had a high quality. The protocol of our study was registered through PROSPERO (register number: CRD42022353987).

Database search
We searched the Web of Science, PubMed, Scopus, Cochrane CENTRAL, and EMBASE from inception until August 2022. Additionally, all references listed in all eligible articles and any prior meta-analyses on the same topic were retrieved to identify any other missed relevant citations. The following search terms were used: ('conventional' OR 'traditional' OR 'open') AND ('endoscopic') AND ('septoplasty' OR 'septal deviation' OR 'deviated nasal septum' OR 'nasal obstruction').

Eligibility criteria and screening
Two reviewers independently screened the retrieved references according to the eligibility criteria. The following criteria were applied to include the studies in our systematic review: trials whose patients suffered from any type of septal deviation; studies whose intervention was endoscopic septoplasty; studies in which comparator groups received conventional septoplasty; studies that assessed any of the following outcomes: postoperative nasal obstruction relief, postoperative nasal discharge relief, postoperative contact point headache relief, postoperative improvement in nasal obstruction and septoplasty effectiveness (NOSE) score, intraoperative and postoperative hemorrhage, mucosal adhesions and synechiae, persistent deviation, and septal tear; and randomized control trial (RCT) study design.
We excluded different studies for the following reasons: studies published in journals not indexed in Web of Science, PubMed, Scopus, Cochrane, or EMBASE; animal studies; nonrandomized trials and observational studies; studies that were not in English; abstract only; and study data that were not reliable for extraction and analysis.

Data extraction
Data extraction was performed using an offline data extraction sheet after further checking to avoid any inclusion of data published in duplicate. The following data were extracted: study ID (first author and publication year), surgical technique, site, follow-up period, age, sex, intraoperative time, deviation type, NOSE score, inclusion criteria, conclusions, and main outcomes, which were as follows: Primary outcomes: postoperative nasal obstruction relief, intraoperative and postoperative hemorrhage, mucosal adhesions and synechiae, and persistent deviation. Secondary outcomes: postoperative nasal discharge relief, postoperative contact point headache relief, postoperative improvement in NOSE score, and septal tear.

Risk of bias assessment
Two authors independently assessed the quality of the included trials using the Cochrane risk of a bias assessment tool for randomized controlled trials (RCTs) [13] . This tool comprises the following parameters: selection, performance, detection, attrition, reporting, and other possible sources of bias. The authors' judgment was categorized as 'high', 'low', and 'unclear' risk of bias. Discrepancies were resolved through discussion or by a third assessor.

Data synthesis
Regarding dichotomous outcomes, risk ratios (RR) were pooled with 95% CIs using the Mantel-Haenszel analysis method. Continuous outcomes were pooled as mean differences (MDs) between the two groups with 95% CIs using the inverse variance method. The fixed effects model was first applied if the effect estimate was pooled from homogenous studies; otherwise, the random effects model was applied. We investigated the statistical heterogeneity between studies using the I 2 statistics χ 2 -test, with P > 0.1 considered as heterogeneous and I 2 ≥ 50% suggestive of high heterogeneity. Additionally, wherever possible, we performed subgroup analyses of the outcomes reported after shortterm (less than 6 months) or long-term (after one year) follow-ups to assess the results after each period. Publication bias assessment using funnel plots was performed for outcomes reported in 10 or

HIGHLIGHTS
• Both conventional and endoscopic septoplasty have drawbacks. • Our review evaluated the latest randomized clinical trial of conventional and endoscopic septoplasty. • Endoscopic septoplasty resulted in overall better patient outcomes. • However, most studies had moderate evidence; more welldesigned research is needed in this field.
more studies by visual inspection of the funnel plots. The Review Manager software version 5.4. was used for all statistical analyses.

Risk of bias assessment
Four of the included studies [14,17,19,25] had a low risk of bias regarding randomization. However, although the remaining studies stated that they were randomized, they did not clarify if this involved random sequence generation or allocation. Twelve of our studies were open-label because of the nature of the procedures [8,[14][15][16][18][19][20][21][22][23][24][25] . All the included studies had a low risk of bias regarding attrition and reporting. A summary of the risk of  1. An informed consent was obtained from the participants 2.
Patients presented with nasal obstruction as main symptom 3. Underwent a full ENT examination.
Postoperative NOSE score. ' The endoscope allows precise resection of the pathological areas without the need of an extended dissection. It is associated with a significant reduction in the patient's morbidity in the postoperative period. However, the endoscope has its own limitations which include loss of binocular vision and the need for frequent cleaning.' Conventional septoplasty, 15   'Endoscopic aided septoplasty was found to be safe, effective and conservative approach with better patient compliance, shorter recovery time and greater stability of remaining septum.' Conventional septoplasty, 25 (50) bias assessment is shown in (Supplementary Figure S1, Supplemental Digital Content 3, http://links.lww.com/MS9/ A162).

Septal tear
Six studies reported septal tears in 355 patients [8,14,16,17,21,22] . The pooled RR after short-term follow-up showed that endoscopic septoplasty significantly reduced the risk of septal tear

Discussion
Our analysis based on 13 RCTs favored endoscopic septoplasty over conventional septoplasty in terms of postoperative nasal obstruction relief, duration of surgery, intraoperative and postoperative hemorrhage, mucosal adhesion, and synechiae. Regarding persistent septal deviation and septal tear, endoscopic septoplasty had the upper hand during the short-term follow-up period only. There was no statistically significant difference between traditional and endoscopic septoplasty in any of the other outcomes that were considered.
Our findings suggest that the endoscopic approach is preferable because of the endoscope's enhanced illumination, which allowed for better visualization, limited flap elevation, minimized cartilage removal, allowed for good septal readjustment, and accurately symmetrically corrected septal abnormalities [2,26] .
The findings of previous literature investigating our studied outcomes were mostly consistent with our results [9] . Our findings indicated that endoscopic septoplasty was the preferred method for treating postoperative nasal obstruction, persistent septal deviation, septal tear, intraoperative, and postoperative bleeding, and mucosal adhesion and synechiae. We did not find a difference, but they did in terms of contact point headaches. Nevertheless, their pooled analysis did not match ours because they combined low-quality observational studies with RCTs published in nonindexed journals and did not separate the studies based on the length of time they followed the participants [9] .
Harley et al. [27] found that the surgical correction markedly improved in individuals with nasal blockage and headaches. Additionally, the correction of nasal symptoms, including nasal blockage and headache, was shown to be more successful in the endoscopic-assisted septoplasty group in a study by Nayak  et al. [28] . Removing the middle turbinate and other nasal structures with an endoscope at the same time is effective in some studies for relieving nasal discomfort [29] .
Our results are consistent with those of numerous other studies that have found synechiae formation to be more likely in patients who received conventional septoplasty as opposed to endoscopic septoplasty [23,30,31] . In one study by Talluri et al., synechiae development was observed in 18.6% of the traditional septoplasty group and 4% of the endoscopic septoplasty group [29] .
Chandra et al. and Sherief et al. found that 4% of patients in the endoscopic group and 16% of patients in the conventional group had a persistently deviated nasal septum, which is similar to our findings [23,24] . Talluri et al. also revealed that 13.3% of conventional septoplasties and 6.6% of endoscopic septoplasties were found to involve partial repair [29] . However, some studies reported no difference between either of the two groups [16,17,21] ; this could be due to their small sample size, which might have prevented them from detecting the difference.
Our study had the following strengths that promote it as strong evidence for the comparison of endoscopic and conventional septoplasty: our analysis was stratified according to follow-up duration. This was a very important point to address as some complications, such as synechiae formation, may take a long time to occur, and may lead to recurrent or incomplete deviation  correction. Our evidence was based only on RCTs that were published in indexed journals to maximize the quality of the evidence. This was not the case in a previous meta-analysis on this topic [9] . Most of the pooled studies were homogenous. We only faced heterogeneity in two of our subgroups; we could resolve one of them (postoperative contact point headache relief) by sensitivity analysis. We identified publication bias when possible; this was not assessed in a previous meta-analysis [9] .
One of our limitations is the small sample size of most of our studied trials; moreover, no stratification was made regarding the preoperative status of patients or concomitant diseases with a deviated septum. Also, 12 of the 13 studies were open-label. Furthermore, mixed procedures like septoplasty, turbinoplasty, and FESS surgery were performed, which could have produced erroneous findings. Additionally, the results could be biased by variations in the surgeons' skills and endoscopy experience. In addition, a small number of studies assessed the outcomes over long-term periods (< 12 months), even though we had outcomes with no long-term assessment, or only one study assessed them. The quality of most of the included studies was moderate, with many unclear assessment domains, as they did not report enough data to permit judgment. The Cochrane Handbook for Systematic Reviews of Interventions guides interpreting the results of synthesis to communicate the conclusions of the review effectively. The handbook suggests that when interpreting the results of a systematic review, the quality of the included studies should be considered. For these reasons, the moderate quality of the included studies should be considered when interpreting the results.
Therefore, we recommend further well-designed studies with larger sample sizes, long-term assessment, and stratification of patients according to their preoperative status and concomitant diseases treated during surgery to obtain more powerful evidence.

Conclusion
Our analysis revealed that endoscopic septoplasty was significantly superior to conventional septoplasty in increasing the postoperative nasal obstruction relief rate and reducing the risk of intraoperative and postoperative hemorrhage, mucosal adhesion and synechiae, persistent septal deviation, septal tear, and surgery duration.

Ethical approval
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Sources of funding